Controller for use in an interconnection system

ABSTRACT

An exemplary embodiment of the invention is a controller for use in an interconnection system having a primary connector and a variable number of secondary connectors. The primary connector includes a first detection contact and a second detection contact. The controller includes a first detection port connected to the first detection contact and a second detection port connected to the second detection contact. The controller also includes a processor for monitoring a first signal at the first detection port and a second signal at the second detection port and determining a number of secondary connectors in response to the first signal and the second signal.

BACKGROUND OF THE INVENTION

In existing computing systems, the ability to upgrade or to haveflexibility in system configurations is critical. By design, thesesystems have modular components which allow many variations incombinations and numbers of subsystems. In order for the system tofunction as a complete unit, the system controller or processor shouldbe able to recognize and distinguish between the individual subsystems.One way to accomplish this recognition is to inform the controllermanually. In this case, the user would have to inform the system of whatsubsystems were present and give each subsystem an identification. Thisis tedious for the user and is prone to mistakes. Also, it has to berepeated every time the system configuration changes.

A second method is to give the system a way to identify each subsystemautomatically. This usually involves some sort of presence detectionusing one or more electrical connections which distinguish betweensubsystems. A common example is 72 pin DRAM SIMMs. These parts typicallyhave four presence detect signals which inform the system of the typeand speed of memory which is installed. This sort of presence detectscheme works well when each subsystem has its own, dedicated set ofdetect circuits. The system can check each of these individual circuitsfor the presence of a subsystem. This method does not work, however,when these circuits are bussed together. In this case, a moresophisticated method is required.

When several subsystems are bussed together, each subsystem typicallyneeds unique identifiers or addresses which the controller can use todistinguish between subsystems. To make the subsystems unique, the usermay have to set jumpers or switches on the subsystems to configure themfor proper operation. A problem arises, however, if the design requiresno user intervention and that the subsystems be identical, i.e., thesubsystem has no inherent unique identifier.

SUMMARY OF THE INVENTION

An exemplary embodiment of the invention is a controller for use in aninterconnection system having a primary connector and a variable numberof secondary connectors. The primary connector includes a firstdetection contact and a second detection contact. The controllerincludes a first detection port connected to the first detection contactand a second detection port connected to the second detection contact.The controller also includes a processor for monitoring a first signalat the first detection port and a second signal at the second detectionport and determining a number of secondary connectors in response to thefirst signal and the second signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a controller, a primary connector and a secondaryconnector in an exemplary embodiment;

FIG. 2 depicts the primary connector and second connector mated; and

FIG. 3 depicts a primary connector, secondary connector, and furthersecondary connector mated.

DETAILED DESCRIPTION

An exemplary embodiment of the invention is shown in FIG. 1. FIG. 1depicts a primary connector 100 and a secondary connector 160. Theprimary connector 100 and secondary connector 160 may be circuit boards,but the invention is not limited to printed circuit boardimplementations. The primary connector 100 may correspond to a system(e.g., a memory controller) and secondary connector 160 may correspondto a sub-system (e.g., a memory device). The invention, however, is notlimited to systems and subsystems and is applicable to a variety ofdevices. Also shown in FIG. 1 is a controller 800 connected to theprimary connector 100.

In FIG. 1, the secondary connector 160 is not mated with the primaryconnector 100. The primary connector 100 contains a first detectioncontact 10 and a second detection contact 120. Each of these contacts iscoupled to at first voltage level (e.g., 5 volts) by a separate resistor140 connected to a voltage source. A ground path is also provided atground contact 150 which is connected to ground. A control contact 500is provided for receiving a control signal from controller 800 andaddressing secondary connectors as described herein.

The primary connector 100 mates with a secondary connector 160. Thesecondary connector 160 includes a first contact 170 which makeselectrical contact with first detection contact 110 on primary connector100 and a second contact 171 which makes electrical contact with seconddetection contact 120 on primary connector 100. The secondary connector160 includes ground contact 190 for making electrical contact withground contact 150. Second contact 171 is electrically connected toground contact 190. First contact 170 is coupled to at first voltagelevel (e.g., 5 volts) by a resistor 140 connected to a voltage source. Acontrol contact 510 is also provided for making electrical contact withcontrol contact 500.

The secondary connector 160 may receive a further secondary connector160′ (shown in FIG. 3), identical to secondary connector 160, atcontacts 520, 180, 181 and 191. Contact 520 is electrically connected tocontact 510. Contact 180 is floating. Contact 181 is electricallyconnected to first contact 170 and contact 191 is connected to groundcontact 190. Detection of the presence of a secondary connector 160 atprimary connector 100 will now be described. When no secondaryconnectors 160 are mated with primary connector 100, no connections aremade to first detection contact 110 or second detection contact 120. Dueto the internal pull up resistors 140 on the primary connector 100, thefirst detection contact 110 and second detection contact 120 are both atthe first voltage level. By monitoring detection contacts 110 and 120and sensing the first voltage level on both pins (shown as level 1 inFIG. 1), controller 800 connected to primary connector 100 can determinethat no secondary connectors 160 are mated with primary connector 100.

FIG. 2 shows the connections when secondary connector 160 is mated withprimary connector 100. When a single secondary connector 160 isconnected to primary connector 100, first contact 170 makes electricalcontact with first detection contact 110, second contact 171 makeselectrical contact with second detection contact 120, ground contact 190makes electrical contact with ground contact 150 and control contact 510makes electrical contact with control contact 500. The electricalconnection between ground contact 190 and second contact 171 causessecond detection contact 120 to be connected to ground. First detectioncontact 110 remains at the first voltage level. Controller 800 (FIG. 1)monitoring detection contacts 110 and 120 will detect first detectioncontact 110 at the first voltage level (e.g., 1) and second detectioncontact 120 at ground (e.g., 0) indicating that a single secondaryconnector 160 is mated to primary connector 100.

FIG. 3 depicts an additional secondary connector 160′ mated to secondaryconnector 160. The additional secondary connector 160′ is identical tosecondary connector 160 and includes similar contacts and internalconnections. When the additional secondary connector 160′ is mated tosecondary connector 160, several additional electrical connections aremade. Control contact 510′ makes electrical contact with control contact520, further first contact 170′ makes electrical contact with contact180, further second contact 171′ makes electrical contact with contact181 and ground contact 190′ makes electrical contact with ground contact191. Ground contact 190′ is connected to ground through ground contact191, ground contact 190 and ground contact 150. Ground contact 190′ isalso connected to further second contact 171′ which mates with contact181. As described above, contact 181 is connected to first contact 170which mates with first detection contact 110. This causes firstdetection contact 110 to be connected to ground. Second detectioncontact 120 is connected to ground through secondary connector 160.Accordingly, the controller 800 monitoring detection contacts 110 and120 detects a logic low (e.g., 0) on both first detection contact 110and second detection contact 120. This indicates that a secondaryconnector 160 and an additional secondary connector 160′ are connectedto primary connector 100. The invention is not limited to detection ofonly two secondary connectors but can be expanded to provide fordetection of any number of secondary connectors.

The exemplary embodiment shown in FIGS. 1-3 also allows the controller800 to address multiple secondary connectors without the need for uniqueidentifiers. Through the control signal applied to control contact 500,the controller 800 may select either secondary connector 160 orsecondary connector 160′. Control input 510 is connected to a controlcircuit 700. The control circuit 700 is also connected to first contact170 though contact 181. Control circuit 700′ is similarly configured.The control circuit 700 implements an exclusive or operation between thecontrol signal and value at contact 170. The output of the exclusive oroperation is used as a select signal to select either secondaryconnector 160 or secondary connector 160′.

When both secondary connector 160 and secondary connector 160′ are matedto primary connector 100, first contact 170 in secondary connector 160will be grounded or low. Further first contact 170′ of secondaryconnector 160′ will be at the first voltage or high. If the controlsignal is high, the output of control circuit 700 will be highindicating selection of the secondary connector 160. The output ofcontrol circuit 700′ will be low indicating that secondary connector160′ is not selected. In the opposite case, if the control signal islow, the output of control circuit 700 will be low indicating that thesecondary connector 160 is not selected. The output of control circuit700′ will be high indicating selection of the secondary connector 160′.In this manner, the controller 800 interfacing with primary connector100 can manipulate the state of the control signal to select eithersecondary connector 160 or secondary connector 160′.

The controller 800 connected to primary connector 100 detects the numberof secondary connectors 160 mated with the primary connector 100 andaddresses specific secondary connectors. The controller 800 may be avariety of devices including a memory controller. Controller 800includes a first detection port 802 connected to first detection contact110 and a second detection port 804 connected to second detectioncontact 120. To detect the number of secondary connectors 160, aprocessor 808 monitors the signals at detection ports 802 and 804. Asdescribed above, the signals at detection contacts 110 and 120 indicatethe number of secondary connectors 160 mated to primary connector 100.Processor 808 detects a first signal at first detection port 802 and asecond signal at second detection port 804 to determine the number ofsecondary connectors 160 mated to primary connector 100. It isunderstood that additional detection ports may be utilized on thecontroller 800 to expand the system to additional secondary connectors160. The controller 800 also includes a control port 806 connected tocontrol contact 500 in primary connector 100. As described above, theprocessor 808 can address a specific secondary connector by producing acontrol signal at control port 806. The processor 808 may generatemulti-bit words at control port 806 to address a plurality of secondaryconnectors.

The above-described exemplary embodiments of the invention allow acontroller to automatically identify and address individual secondaryconnectors (e.g., subsystems) in the system without a requirement thatthe individual secondary connectors be uniquely identified. Thiseliminates the need for user intervention and allows the use of multipleidentical secondary connectors which reduces the number of unique parts.

While preferred embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Accordingly, it is to beunderstood that the present invention has been described by way ofillustration and not limitation.

What is claimed is:
 1. A controller for use in an interconnection systemof a computer for connecting between the computer and a plurality ofsubsystems, the interconnection system having a primary connector and avariable number of secondary connectors each associated with arespective subsystem, the primary connector including a first detectioncontact and a second detection contact, said controller comprising: afirst detection port connected to the first detection contact; a seconddetection port connected to the second detection contact; and, aprocessor for monitoring a first signal provided from said firstdetection contact of said primary connector to said first detection portand a second signal provided from said second detection contact of saidprimary connector to said second detection port and determining a numberof secondary connectors in response to a magnitude of said first signaland a magnitude of said second signal.
 2. The controller of claim 1wherein: said processor detects no secondary connectors when said firstsignal is a first voltage and said second signal is the first voltage.3. The controller of claim 2 wherein: said processor detects onesecondary connector when said first signal is a first voltage and saidsecond signal is a second voltage.
 4. The controller of claim 2 wherein:said processor detects two secondary connectors when said first signalis a second voltage and said second signal is the second voltage.
 5. Thecontroller of claim 1 further comprising: a control port connected to acontrol contact in the primary connector; wherein said processorprovides a control signal to said control port, said control signaladdressing one of the secondary connectors.